Accessory dwelling unit companies

Looking for accessory dwelling unit companies in San Jose, CA? Call AccessoryDwellingUnit Services for a contact a provider — no obligation. Licensed adu builders serve San Jose and the surrounding area, and you'll get straight answers on timing and what affects the price.

Last updated: September 24, 2026

What affects the price

Building an ADU involves several moving parts that shape your total investment. The final figure depends heavily on whether you choose a prefab unit or a custom build from the ground up. Site conditions are another major factor; if your property requires extensive grading, utility trenching, or foundation work, costs will climb. You also have to consider your choice of finishes, like high-end appliances or custom cabinetry. Navigating local permit fees and impact assessments also adds to the total.

About this service

These companies provide comprehensive support for homeowners, often pairing design experts with construction crews to handle the entire project under one roof. They are helpful when you want to avoid hiring separate architects and builders. You should look into these companies when you want a streamlined experience and a single point of accountability for your backyard project from start to finish.

Frequently asked in San Jose

What are the disadvantages of ADUs?

While ADUs offer many benefits, potential disadvantages include initial construction costs and potential impacts on privacy or parking for existing residents. You might also need to consider how an ADU will affect your property's landscaping or utility usage. Discussing these points with a local pro is important for a balanced perspective.

How much does an ADU cost in San Jose?

The cost of an ADU in San Jose varies significantly based on size, materials, and complexity. Factors like site preparation, foundation work, and specific finishes all play a role. Getting a personalized quote is the best way to understand potential expenses for your specific project.

What are the rules for ADUs in California?

Is an ADU allowed in San Jose?

Yes, San Jose actively encourages the development of ADUs to address housing needs. There are specific zoning and building code requirements that must be met. Consulting with local experts ensures your proposed ADU complies with all city regulations.

What is involved in building an ADU in San Jose?

Building an ADU involves design, obtaining permits, site preparation, construction, and final inspections. This includes everything from pouring the foundation to installing plumbing and electrical systems. The pros who serve San Jose neighborhoods handle these complex steps.

Also serving nearby: Burbank · Santa Clara · Sunnyvale · Fremont · Hayward

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More on this: HUD ADU resources — ADU policy and financing research.

Service area details

969,655residents

5,449per sq mile

8ZIP codes served

Serving all of San Jose — population 969,655; about 5,449 residents per square mile across 177.9 sq mi. ZIP codes covered include 95025, 95101, 95103, 95106, 95108, 95109, 95110, 95111.

Neighborhoods served in San Jose: Willow Glen, Japantown, Rose Garden, Almaden Valley, Downtown San Jose — and every surrounding area.